Springtails pesky but harmless
January 11, 2007
Sonia Day
PLANT DOCTOR
QI have a mature croton in a pot. The soil surface has been overrun with minuscule white bugs, less than a millimetre long. There are literally billions of them milling about! They jump a tad when the plant gets a watering, but have not migrated to any other plants in the house. How should I treat them? What are they?
AProbably springtails. These are curious little critters, about 1- to 2-mm long, which entomologists classify as "insects" even though they have no wings and can't fly. Instead, as their name suggests, springtails behave a bit like mobs of crazed kangaroos. When disturbed, they will jump abruptly (sometimes leaping 10 times the length of their bodies) propelled by a device on their stomachs called a farala.
There are, amazingly, 700 kinds of springtails around the world, all belonging to the Collembola family. However, most look very similar – white, wingless and tiny – and they usually congregate and multiply in vast numbers. Don't panic, though. They're harmless. In fact, the presence of springtails in soil is an indication of lots of healthy, rich organic matter. Companies that make environmental pest control products call these funny little creatures "beneficial bugs" and sell them to outdoor gardeners.
Springtails are also easy to get rid of. Simply let the pot go dry and they should magically disappear. If they don't (and are annoying) try spraying the soil surface with a pyrethrin based insecticide. I recently discovered one with the delightful name of Doktor Doom. Made by a company in Alberta, this product contains the highest pyrethrin concentration of any plant spray of its type in Canada and also works pretty well on aphids and whitefly. You can find it at Sheridan Nursery (for other suppliers, contact doktor doom@shaw.ca) in a lime-green aerosol can with the word "Botanics" on it.
A note to the environmentally-conscious: pesticide products made from pyrethrins are still permitted in Toronto because they're made with an oil extracted from a flower familiar to most of us Chrysanthemum cinerarieafolium. Insects ingest this oil and it poisons them, yet there's no apparent residual damage to the environment. However, don't overuse pyrethrin (also called pyrethrum). It can irritate skin, some pets are allergic to it, and avoid getting it into anything you're going to eat or drink. Haul the pot outside (the weather's still warm enough) and do it there.
One point in favour of a dollop of Doktor Doom is that it contains only pyrethrins. Some other sprays of this type include piperonyl butoxide too, because it increases the bug zapping power. However, piperonyl butoxide is now classified as one of those "iffy" chemicals with a host of dubious attributes. Avoid using it, if you can.
But back to that buggy croton: those jumping jacks may in fact not be springtails, but two other houseplant horrors preparing to torment you. Larvae of fungus gnats look white, shiny, black-headed and vaguely transparent. Mealybugs, which are small and white (or greyish) also sometimes congregate among surface roots, and then later migrate upwards, to leaves and stems.
Whatever the culprit, pyrethrin spray will probably help. Also, if it's practical, dunk the entire pot into a bath of insecticidal soap mixed in water. Leave for ten minutes, then remove and rinse.
Send your brief gardening questions to Sonia Day through her website at soniaday.com.
Toronto Star